2001 Ford Taurus Leaking coolent

My serpentine belt broke I drove it to get it home it died and I had to have it towed. I went the next day got a belt for it the next day started it and it had a blown head gasket so I changed both of them and drove it for a while it was fine but then it started to leak from the back of the mother so I went and got some Blue Devil put it in the car the leak stopped so I thought it was fine the next morning I was driving it was fine then smoke started rolling out of the hood and it was not overheating I pulled over and looked at
It and coolent was pouring out of it same place the leak was so I thought it was the rear head gasket so I changed it started it drove it around the block came back let it idle a little while and then I noticed smoke again and it was not over heating and leaking from the back of the mother again and from the radiator where the thermostat is so I replaced the thermostat and the rear head gasket again started let it idle and I saw smoke again and it was not overheating and leaking on the exhaust from the back of the motor I can't figure out what's wrong with it. PLEASE HELP